Pinpoint Test S: All The Trailer Lamps Are Inoperative

Trailer Lamps

Pinpoint Tests

Pinpoint Test S: All The Trailer Lamps Are Inoperative

Refer to Wiring Diagram Set 11, Fuse and Relay Information for schematic and connector information Diagrams By Number.

Refer to Wiring Diagram Set 95, Trailer/Camper Adapter for schematic and connector information Diagrams By Number.

Normal Operation

The trailer tow connector is supplied a single chassis ground for all of the trailer lamps.

All the trailer lamp relays share a common ground.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Trailer tow connector
- Trailer



PINPOINT TEST S: ALL THE TRAILER LAMPS ARE INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Before beginning diagnostics, visually inspect the trailer tow connector for signs of corrosion or damage. Repair or install a new trailer tow connector as required.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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S1 CHECK THE RELAY GROUND CIRCUIT FOR AN OPEN


- Ignition OFF.
- Disconnect: Trailer Tow Parking Lamp Relay.
- Measure the voltage between the trailer tow parking lamp relay pin 3, BJB, circuit SBB57 (RD), face side and the trailer tow parking lamp relay pin 2, circuit GD123 (BK/GY), BJB face side.




- Is the voltage greater than 10 volts?

Yes
GO to S2.

No
REPAIR circuit GD123 (BK/GY) for an open. TEST the system for normal operation.

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S2 CHECK THE TRAILER TOW CONNECTOR FOR CONTINUITY TO GROUND


- Disconnect: Negative Battery Cable.
- For vehicles equipped with a class I trailer tow package, measure the resistance between the trailer tow C4098-4 RAT08 (WH), harness side and ground.




- For vehicles equipped with a class II trailer tow package, measure the resistance between the trailer tow connector ground supply pin, circuit RAT08 (WH), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.

No
For vehicles equipped with a class I trailer tow package, REPAIR circuit RAT08 (WH) for an open. TEST the system for normal operation.

For vehicles equipped with a class II trailer tow package, GO to S3.

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S3 ISOLATE THE TRAILER TOW CONNECTOR


- Disconnect: Trailer Tow C4099.
- Measure the resistance between the trailer tow C4099-2, circuit RAT08 (WH), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
INSTALL a new trailer tow connector. TEST the system for normal operation.

No
REPAIR circuit RAT08 (WH) for an open. TEST the system for normal operation.

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